In various and sundry processes, an apparatus may be needed to dispense carefully controlled amounts of a composition as various products are being formed or as various processes are taking place. Such dispensing devices may be needed, for instance, during the production of pharmaceuticals, chemical products, semiconductor products including integrated circuits, food products, and the like. In some applications, a dispenser is needed that is capable of accurately and reliably dispensing relatively small amounts of a fluid at periodic intervals.
For example, in one particular embodiment, dispensing devices as described above are used in order to inject a composition into a fertilized egg, such as a poultry egg. In the past, eggs have been injected with vaccines, vitamins, nutrients, and antibiotics. The compositions that are injected into the egg have been employed in order to decrease post-hatch mortality rates and/or to increase the potential growth rates of the resulting poultry. Antigens have also been injected into live eggs in order to incubate various substances used in vaccines which have human or animal applications.
In the past, in ovo injections of substances into poultry eggs have occurred by piercing the eggshell to create a hole and then extending an injection needle through the hole and into the interior of the egg. The needle, for instance, may be injected into the embryonic fluid contained in the egg. Examples of injection devices and/or egg treatment methods are disclosed in U.S. Pat. Nos. 4,458,630; 4,681,063; 5,028,421; 5,176,101; 5,339,766; 5,438,954; 5,900,929; 6,286,455; 6,506,385; and 6,668,753 which are all incorporated herein by reference.
In prior systems, eggs were conveyed down a conveyor on a tray at relatively high speeds. For example, the eggs may be conveyed at a rate of about 20,000 eggs per hour. At a certain point in the process, motion of the eggs is halted while the eggs are injected with a treatment composition. In many applications, a plurality of injection devices are brought down upon the eggs simultaneously. The injection devices are configured to release a treatment composition through the needle whether or not an egg is present below the needle. The excess fluid is then channeled off the conveyor and discarded. As can be appreciated, this technique creates a significant amount of waste of the treatment composition which, in many applications, is relatively expensive. In addition, problems have also been experienced in dispensing controlled amounts of the treatment composition. In particular, prior art dispensing devices have not only been somewhat cumbersome but have also not been capable of uniformly and repeatedly dispensing controlled amounts of the treatment composition with the desired accuracy.
In view of the above, a need exists for an injection system that includes controls configured to sense the presence of an egg for only releasing a treatment composition when an egg is present. A need also exists for an injection system capable of dispensing precise and controlled amounts of a treatment composition at periodic intervals.
In addition, a need also generally exists for a dispensing device for use in other industries that is capable of repeatedly dispensing uniform and precise amounts of a chemical composition during a manufacturing process. In addition to being well suited for use in ovo injection systems, such a device is also well suited for use in the pharmaceutical industry, the semiconductor industry, the food processing industry, the chemical manufacturing industry, and the like. In the above fields, for example, a need currently exists for a compact dispensing device for dispensing relatively small amounts of a composition that is capable of attaining the above described goals.